1. Field of the Invention
The present invention relates to a sheet feeder having a manual feed tray, and to an image forming apparatus including the sheet feeder.
2. Description of the Related Art
Image forming apparatuses such as a copying machine, a printer, and a facsimile machine include an image forming section that forms a toner image on a sheet of paper (sheet) and a paper feeder that feeds a sheet of paper to the image forming section. Generally, an image forming apparatus includes both a paper feeder that feeds a sheet of paper from a paper cassette to the image forming section and a paper feeder that feeds a sheet of paper from a manual feed tray on which the sheet of paper is mounted by a user to the image forming section.
As a conventional image forming apparatus, an apparatus is known in which a manual feed tray is provided on a front cover of an apparatus main body and an opening operation for pulling down the manual feed tray from the front cover is to be performed in two stages. Accordingly, an impact caused when pulling down the manual feed tray is suppressed. As a result, an impact sound is suppressed and, at the same time, an impact acting on components of the manual feed tray is suppressed.
However, in the conventional image forming apparatus, the manual feed tray and the front cover are coupled by a link lever. Therefore, when a large load acts on a sheet mounting surface of the manual feed tray in a state where the manual feed tray is assuming an open posture, the load is transferred to the front cover via the link lever. Therefore, the front cover may open inadvertently.
A paper conveying path for conveying a sheet of paper is provided on a rear face of the front cover which faces the inside of the apparatus main body. A plurality of conveying rollers is arranged on the paper conveying path. Each of the plurality of conveying rollers is in contact at a predetermined contact pressure with a corresponding conveying roller arranged on the side of the apparatus main body. Therefore, when the front cover inadvertently opens due to the load, an impact generated upon the opening of the front cover may disrupt a contact pressure balance between the conveying rollers and may create a gap between the conveying rollers. Disruption of contact pressure balance causes paper conveyance failure. In addition, the impact generated upon the opening of the front cover may damage components such as the link lever.